Cohorts of 3-6 patients receive escalating doses of flavopiridol until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which at least 2 of 3 or 2 of 6 patients experience dose-limiting toxicity. (Phase I closed to accrual effective 10/24/2003). Once the MTD is reached, additional patients are accrued to receive flavopiridol at the recommended phase II dose.